Bald Eagle Gold Corp. (TSX – V: BIG) recently went public on the TSX Venture Exchange, sparking a great deal of interest in their flagship Hot Springs Property in Humboldt County, Nevada. One of the reasons the asset is so promising is that both historical data and modern science point to the fact that the site has good potential to host epithermal gold deposits. But what are epithermal deposits and why are they so important?
What Are Epithermal Deposits?
Epithermal gold deposits are underground deposits that contain a network of veins of silica and gold which are disseminated throughout the economic mineralized rock and can be mined.
Epithermal deposits are distinguished from low-grade bulk tonnage deposits such as porphyries in that the gold is carried towards the surface in very hot water flows which travel upward through crustal rock in faults and other fractures. In porphyry deposits gold travels in migrating flowing rock. In epithermal deposits, the gold can be also be concentrated at the historical surface (called the “paleosurface”) in hot springs. The gold can also be concentrated as atmospheric water percolates into the ground and circulates in underground rock after heating.
Why are Epithermal Gold Deposits so Sought After?
Epithermal gold deposits may contain high-grade gold in the range of one ounce per tonne or more. Those grades are called bonanza grades and can be profitably mined by underground methods. Epithermal deposits can also be lower grade at one gram or less per ton. The lower grade ore bodies tend to be mined profitably as open pits.
Gold Deposits in Nevada
Nevada was originally called ‘the Silver State’ because of the size and quality of epithermal silver deposits discovered there. However, from the late 1870s onwards, the majority of epithermal bonanzas discovered in Nevada contained more gold than silver.
To give you an idea of just how much gold there is in Nevada, in 2018, 83% of the gold produced from the United States came from Nevada. That same year, Nevada accounted for 5.3% of the total gold produced worldwide.
Not only does Nevada produce vast amounts of gold, but it is also home to some of the richest epithermal gold deposits in the world. This includes the Comstock Lode in what is now known as the Walker Lane gold trend. This trend is associated with high-yielding mines such as Midas and Fire Creek.
Hot Springs Project
The Hot Springs Project is Bald Eagle Gold Corp.’s flagship asset and it spans nearly 12,000 acres between the Battle Mountain and Getchell-Comstock gold trends. Surrounding the site there are 18 mines, including world-class epithermal mines like Midas and Fire Creek, both of which are less than 100 kilometres from Hot Springs. The primary gold targets for Hot Springs are epithermal gold deposits, but the company also has good potential to find Carlin-type gold deposits.
Humboldt County, where the Hot Springs Property is located, is famous for high-yielding Carlin-type gold deposits. These are similar to epithermal deposits in that they are created by hydrothermal fluids. These deposits do not tend to form in veins, but are in fact diffusely distributed in rock as very small particles. Some examples of renowned Carlin-type mines include Turquoise Ridge, Twin Creeks, and of course Carlin, the town these type of deposits are named after.
Two main kinds of sedimentary assemblages, carbonate and silicic rocks, are the most common host rocks of sedimentary rock-Carlin-type hosted gold deposits in north-central Nevada. The rock hosts include silty limestone and dolomite, siltstone, sandstone, conglomerate, and argillite with interbedded clay and shale. Bald Eagle’s Hot Spring Property has the potential for Carlin-type deposits as well as epithermal gold deposits.
The reason there are so many gold deposits in this region is because it is a rift zone where there are multiple underground structures that at one time funnelled mineralizing fluids. The fact that Hot Springs sits in this rift zone at the intersection of two major gold trends featuring both epithermal and Carlin-type gold deposits makes it a highly prospective asset.